Telegraph system



M. AMANN TELEGRAPH SYSTEM Filed Oct. 31, 1934 MAX/474m Ottoman.

Patented May 3, 1938 ,gu1s111"so STATES PATENT OFFICE Application October 31, 1934, Serial No. 750,881 In Germany October 31, 1933 with-an unequally sub-divided source of current Whichisconnected to the line during the transmission of signals in eitherdirection, but is disconnected therefrom in the inoperative state of the installation, is also provided at each station with a linerelay which is connected to the line both in the operative and in the inoperative,

state and, in the inoperative state, to the return line, and is further provided, at each station, with auxiliary switch means which, when a station is brought into operation, connect the line relay at that station in series with the transmitting contact so, that either of the unequal parts of the source of v current at that station can then be connected ,to'the line. By means of this arrangement, it is, possible to record the signals sent out by a station at the transmitting station. It also allows the source of current to be disconnected from the line when the installation is not operating and to switch in the sources of current at the beginning of the signal transmission by means of the receiving relay which is always connected to the line at the receiving station. The sources or current can likewise be switched in by the receiving relay forall the other circuits of the receiving station, for example, the circuits for the driving motor, the receiving magnet of the printer and so on, so that it is not necessary to consume current when the station is not operating. This leadsto an appreciable saving in current.

, In order that the invention may be thoroughly understood and be more readily carried into effect, an example of construction in accordance therewith will now be described with reference to the accompanying drawing in which:

' Figure 1 illustrates diagrammatically the connections of a line circuit to two interconnected telegraph stations.

Figure 2 shows the complete connections of ,two telegraph stations operating onthe startstoprsystemwhich are interconnected by a line.

A source of current consisting of two batteries of-different sizes Bi and B2 or Bi and B2 is provided at each of .the, two stations A and B (Figure 1). The receiving relays PR and PR are permanently connected tothe two Wires of the-transmission line L. The transmitting contact-sic or sic allows one or the other of the two batteriestobe connected to theline. An auxiliary switch Z or Z isalso provided at each of the two stationsby means of which, the sources of ourrent are disconnected from the line when the station is not operating and directly connect the two wires of the transmission line L together. Therefore, in the inoperative position, which is shown in Figure 1, no current flows through the line L. The receiving relays PR and PR are polarized and hold their contacts in the illustrated position. In order that the circuits of the two stations may be constructed equally, the two wires of the transmission line are crossed as shown.

If the station A is to start the transmission of a signal to the station B, it first of all actuates the auxiliary switch Z so that this closes the contact 2.

through the receiving relays PR and PR. The direction and strength of this current from the battery BI is, however, such that the polarized relays PR and PR do not throw their armatures.

At the beginning of the signal transmission the transmitting contact sic is thrown as described above so that the battery B2 is connected to the line instead of the battery Bl. The voltage of the battery B2 is about three times that of the battery BI and the current from it flows through the line L and the receiving relays PR and PR. in the opposite direction to that from the battery Bl. These relays are energized by this current which is strong enough to ensure that their contacts will be actuated. As soon as the relay PR throws its armature, the auxiliary switch Z at the station 13 is actuated so that the battery Bl is connected to the line, the current from which runs in the opposite direction to that of the battery B2 of the station A. The voltages of the batteries Bi and B2 are the same as those of the batteries Bi and B2. Therefore, as the voltage of the battery BI is only one-third of that of the battery B2, the current still flows through the line in the same direction but is weakened.

During the transmission of the signals, which are of the Baudot type and thus consist each of 5 separate current impulses, the transmitting contact sic swings over so that the battery B2 and the battery B! at the transmitting station are connected alternately to the line while the battery Bl at the receiving station B remains constantly connected to the line. When the battery Bl is connected to the line, the voltage of the current is equal to the sum of the voltages of the battery Bl at the sending station and the battery B! at the receiving station. Thus, if for example, the voltage of each of these two batteries is 6 volts, then a current of 12 volts flows through the line in such a direction that the re- In this way, the battery BI is connected to the line and current flows through the line and 4 ceiving relays PR and PR throw their armatures into the inoperative position. When, however, the battery B2 is connected to the line, the voltage of the current is equal to the difference in the voltages of the batteries B2 and Bi. Thus, if the voltage of the battery B2 is, for example, 18 volts, then a current of 12 volts flows through the line L but in the opposite direction to that of the previous 12 volt current, so that the receiving relays PR and PR now throw their arniatures into the operating position.

At the end of the transmission, the auxiliary switches Z and Z are switched out so that, in the inoperative condition, the line L becomes devoid of current and the two wires of the line are directly inter-connected. In this way, the effects of neighbouring lines and disturbances due to cross talk are avoided.

The stations A and B illustrated in Figure 2 are constructed as printing telegraphs working on the start-stop principle. The transmitting contacts sic and sic are controlled by rotary transmitting distributors SV and SV, the shafts of which can be driven by the motors M and M The construction of these transmitting distributors is known in itself and is described, for example,in my prior U.S.Patent No.1,983,960. The motors M and M can be driven either by direct current or by alternating current. The rate of rotation of the motors is regulated by centrifugal contacts Elk: and Elk which have glow lamps G2 and Gi connected in parallel with them so that a visual indication is given of the rate of rotation of the motors.

The transmitting keys ET control mechanically, in a known manner, 5 combination bars KS which influence the cams of the transmitting distributor SV. This distributor SV is connected by a frictional drive to a motor M, but is held in the position shown in the drawing by a pawl K. The transmitting keys also influence a special change over bar U which latches the transmitting distributor SV by means of the pawl K so that it can be driven by the motor M. Only one of these transmitting keys ET is illustrated in the station A. This serves for switching in the transmitter and also actuates a contact elc.

At each of the two stations A and B, there is also a receiving magnet EM or EM which, in a known manner, mechanically controls the printer of the receiving apparatus so that signals are printed by means of current impulses, under the control of the receiving magnet EM. Finally, at each of the two stations, an auxiliary switch Z or Z is provided which is controlled by a magnet ZM or ZM and actuates various contacts l-4. If the magnet ZM or ZM has attracted its armature once and the contacts of the auxiliary switch Z and Z have thus been reversed, the contacts remain reversed for a longer time and no energization of the magnet ZM or ZM takes place. It is only then that the contacts are returned to the normal position by a cam N driven by the motor M. The construction of this auxiliary switch is known in itself and is described in detail in U. S. Patent No. 1,964,841. The magnet ZM can be energized by direct current or by alternating current. A resistance VB and a condenser CF are connected in its energizing circuit which normally decrease the energizing current to such an extent that the magnet can no longer attract its armature. It is only when the condenser CF is short circuited that the energizing current increases so that the auxiliary switch Z is actuated. The condenser CF can be short circuited either by the contact elc, which is controlled directly by the key ET, or by contact of the receiving relay PR when the latter is in its working position,

Any existing alternating or direct current mains NA or NA can provide the source of current to be connected to the line L for the signal transmission. In the arrangement illustrated in Figure 2, it is assumed that the station A is connected to alternating current mains NA. A rectifier G1 is connected to the secondary winding of a transformer Tr through a series resistance VW. The rectified current circuit, includes choke coils Dr and condensers C for smoothing the direct current and a potentiometer Pot from which the voltages BI and B2 are tapped off. An indicator MA is provided for indicating the strength of the current. The station B in Figure 2, is shown connected to direct current mains NA. Here, a potentiometer Pot from which the required voltages Bi and B2 can be tapped is connected to the mains. Chokes Dr and conclensers C are also provided in the direct current circui for smoothing the direct current. As considerably stronger currents are required for supplying the motors M and MI and for energizing the magnets ZM and ZM controlling the auxiliary switches Z and Z than for the signal transmission, when connection is made to alternating current mains, these will be energized directly with alternating current. The primary winding of the transformer Tr of the station A is, for this purpose, in the form of an autotransformer, so that the alternating voltage res quired for supplying the motor M and energizing the magnet ZM can be obtained directly. In this way, the system is made appreciably more economical, because only the relatively weak currents which are necessary for the signal transmission have to be rectified. When the connec-- tion is to direct current mains, as is illustrated in the case of station B, the current required by the motor M and the magnet ZM is tapped off directly from the potentiometer Pot.

The method of operation of the arrangement is as follows. As soon as the switching key ET is actuated at the station A, the contact ek is closed and, at the same time, the combination bars KS are set so that the transmitting distributor SV is prepared for sending out a signal formed of 5 negative current impulses. The contact ek short circuits the condenser CF so that the magnet ZM is energized and attracts its armature and the auxiliary switch Z reverses its contacts. The contact I of the auxiliary switch Z closes the circuit for the motor M which then starts to run. The contact 2 of the auxiliary switch Z connects the line L to the source of current BI and the contact 4 of the auxiliary switch Z closes the local energizing circuit for the receiving magnet EM which runs through the contact of the receiving relay PR. When the key ET is actuated, the pawl K is actuated by the bar U and thus, the transmitting distributor SV is driven by the motor in a manner not shown, and the transmitting distributor makes one rotation together with the motor M. The motor quickly reaches its operating rate of rotation and maintains then this under the control of the centrifugal contact Flk. As soon as the start section of the transmitting distributor SV arrives beneath the transmitting contact sit, the latter is mechanically thrown and thus the voltage B2 is impressed on the line L so that a negative current flows through the line which actuates the receiving relays PR and PR. The path of this current is as follows:B2 (18 volts), operating contact of sic, relay PR, line L, contact 2 of the auxiliary switch Z, relay PR, line L, contact 2 of the auxiliary switch Z, B2 (+18 volts).

When this circuit is established, the polarized line relays are forcibly actuated.

As the transmitting distributor S-V was prepared for sending negative current signals by means of the setting of the combination bars KS which took place on actuation of the key ET, the transmitting contact sic holds its circuit closed while the sections l5 of the transmitting distributor SV pass in succession beneath the contact sic. It is onlywhen the stop section of the transmitting distributor SV comes under the transmitting contact sic that the contact is returned to the normal position in which the voltage BI is connected to the line L.

7 During the reversal of the armature of the relay PR into the working position, the receiving magnet E-M at the transmitting station A, the circuit of which is closed on actuation of the auxiliary switch Z by the contact 4, is de-energized. The device for printing the signals is constructed in a known manner so that by the energization of the receiving magnet during 5 successive signal impulses, either the printing of a signal takes place or else a setting operation effected in the printer such, for example, as the line feeding of the paper or the like.

At the receiving station B, when the relay PR attracts its armature, the condenser CF is short circuitedso that the current of the magnet ZM is strengthened. This magnet responds and the auxiliary switch Z actuates. The contact I of the auxiliary switch Z closes the circuit of the motor M which then starts to run. The contact 2 connects the line L to the source of current Bl which acts in opposition to the source of current B2 at the transmitting station, so that the current flowing through the line is weakened. The contact 4 closes the circuit for the receiving magnet EM which is controlled by the contact of the receiving relay PR. As the relay PR holds its armature attracted for the duration of 5 successive signal impulses, the receiving magnet EM is de-energized for this length of time so that printing of a signal takes place.

At the end of the transmission of this first switching signal consisting of 5 negative current signals, the transmitting contact sic is again returned by the stop section of the transmitting distributor SV into the normal position and the following circuit is established:Bl (+6 volts), contact sic, relay PR, line L, contact 2 of the auxiliary switch Z, Bl (-6 volts) contact sic, relay PR, line L, contact 2 of the auxiliary switch Z, Bl.

The voltages of the sources of current BI and Bi, which are both of 6 volts, are additive so that a current of 12 volts flows through the line in such a direction that the relays PR. and PR return their armatures again into the inoperative position. The energization of the magnets ZM and ZM is now again interrupted. If, by actuation of the transmitting keys which are not illustrated, successive signals are transmitted through the line, in every case, the magnets ZM and ZM of the auxiliary switches Z and Z are energized on the occurrence of a negative signal so that the relays PR and PR are energized and the contacts of the auxiliary switches remain in the Working position. It is only when the energization of the magnets ZM and ZM is interrupted for a longer time that the contacts of the auxiliary switches are returned by the cams N and N into their inoperative position. These cams which are illustrated diagrammatically can be rotated by the driving motor in a known manner on the occurrence of a longer period of deenergization of the magnets ZM and ZM. The construction and operation of the auxiliary switches are set forth in detail in the aforementioned Patent No. 1,964,841. In this way, the circuits again become devoid of current, the two wires of the line L are connected together, and the local circuit for the receiving magnets EM and E-M'is interrupted. Only the primary winding of the transformer Tr of the station A and the potentiometer Pot of the station E remain connected to the mains. Besides this small loss which thus occurs, no current is necessary in the installation in the inoperative condition.

It is clear that the receiving relays PR and PR are actuated in the two stations both on the transmission of the switching signal which consists of 5 negative current signals and also on the further transmission of all other signal impulses, so that the transmitted text can be recorded in the sending station and, in addition, in spite of the disconnection of the source of current from the line in the inoperative condition, the switching in of the other station can be eiTected from the transmitting station. Besides the auxiliary switches, no further means are provided at the two stations. The auxiliary switch, moreover, controls all the switching steps required for the two stations. The invention is not restricted to the use of a two-wire line, as one wire of the line can, as is known, be replaced by an earthreturn path.

I claim:

1. A telegraph installation, comprising two stations, a line connecting the two stations, a transmitting device at one of said stations for transmitting code impulses, a printing device at the other of said stations for printing signs corresponding to the transmitted code impulses, means for switching-in said devices at each station, and a switching-in key controlling said transmitting device for transmitting a predetermined series of code impulses, said printing device being constructed so as to prevent theprinting of a sign on being influenced by said seriesof code impulses transmitted on actuation of said switching-in key of the transmitting station, and said switching-in means at the receiving station being constructed so as to be actuated by said series of code impulses.

2. A telegraph installation having a start-stop operation, comprising two stations, a line between said stations, a transmitting device at the transmitting station for transmitting a start impulse, a series of variablecode impulses and a stop impulse, a printing device at the receiving station adapted to print signs corresponding to a series of code impulses, a switching-in key at the transmitting station which upon actuation controls said transmitting device for transmitting a start impulse, a series of code impulses corresponding to the start impulse and a stop impulse, said printing device being constructed for preventing the printing of a sign on being influenced by a series of code impulses corresponding to a start impulse and means at the receiving station for switching in the printing device of said station on being influenced by impulses corresponding to a start impulse.

3. A telegraph installation having a double current and start-stop operation, comprising two stations, a line between said stations, an unequally sub-divided source of current at each station, a polarized relay at each station, a printing device at each station controlled by said relay, an auxiliary switch at each station controlled by said relay, a transmitting device at each station for transmitting a start impulse, a series of code impulses and a stop impulse, said transmitting device being constructed for connecting the greater part of the source of current to the line on transmitting a start impulse, a switching-in key which upon actuation controls said transmitting device for transmitting a start impulse, a series of code impulses corresponding to the start impulse and a stop impulse, said printing device being constructed for preventing the printing of a sign on being influenced by a series of code impulses corresponding to the start impulse and said auxiliary switch being constructed for actuating upon being influenced by a series of impulses corresponding to a start impulse, said auxiliary switch controlling contacts on actuation for switching in the printing device.

4. A telegraph system, comprising two telegraph stations and a line including two current paths between said telegraph stations; each of said stations being provided with two current sources of different dimensions connected in series, a transmitting contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the current paths of the line, a polarized receiving relay interposed in one current path of the line and connected with the sending contact, and an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its non-actuated position with the receiver relay and in its actuated position with the connecting point of both current sources.

5. A telegraph system, comprising two telegraph stations and a line including two current paths between said telegraph stations; each of said stations being provided with two current sources of different dimensions connected in se ries, a transmitting contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the current paths of the line, a polarized receiving relay interposed in one current path of the line and connected with the sending contact, an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its non-actuated position with-the receiving relay and in its actuating position with the connecting point of both current sources, an electro-magnet for actuating said auxiliary switch, a connecting key having a contact for closing a circuit for the electromagnet, and a contact controlled from the receiver relay for closing a circuit for said electromagnet.

6. A telegraph system according to claim 5, wherein each of the telegraph stations comprises further mechanical means for setting back the auxiliary switch into the non-actuated position on long non-excitation of the electromagnet.

'7. A telegraph system, comprising two telegraph stations and a line including two current paths between said telegraph stations; each of said stations being provided with two current sources of different dimensions connected in series, a transmitting contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the current paths of the line, a polarized receiving relay interposed in one current path of the line and connected with the sending contact, and an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its non-actuated position with the receiver relay and in its actuated position with the conmeeting point of both current sources; the receiving relay being excitable in the inoperative state of said auxiliary switch by the current of the current source of larger dimension of the other station.

8. A telegraph system, comprising two telegraph stations and a line including two current paths between said telegraph stations; each of said stations being provided with two current sources of different dimensions connected in series, the potentials of the two current sources being in the ratio of l to 3; and each of said stations also including a sending contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the current paths of the line, a polarized receiving relay interposed in one current path of the line and connected with the sending contact, and an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its non-actuated position with the receiving relay and in its actuated position with the connecting point of the two current sources.

9. A telegraph system, comprising two telegraph stations and a line between the stations, said line including two current paths, and each of said stations being provided with two current sources of different dimensions connected in se' ries, a sending contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the paths of the line, a polarized receiving relay interposed in one of the current paths of the line and connected with the sending contact, said sending contact connecting, in its inoperative position, the free pole of the smaller current source with the receiving relay, and each of the telegraph stations being further provided with an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its non-actuated position with the receiver relay and the sending contact and in its actuated position with the connecting point of both current sources.

10. A telegraph system, comprising two telegraph stations and a line therebetween including two current paths, each of said stations being provided with two current sources of different dimensions connected in series, a sending contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the paths of the line, a polarized receiving relay interposed in one of the current paths of the line and connected with the sending contact, an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in its nonactuated position with the receiving relay and the sending contact and in the actuating position with the connecting point of both current sources; each of the two stations also comprising a printing magnet, a local circuit fed from one of the two current sources for the printing magnet, an alternating contact controlled from the receiving relay and suitable to influence the local circuit of the printing magnet, an electromagnet for actuating the auxiliary switch, a local circuit for said electromagnet influenced from the alternating contact of the receiver relay and a switch key having a contact for influencing the circuit for the electromagnet.

11. A telegraph system according to claim 10, wherein the auxiliary switch comprises a plurality of contacts, one of said contacts being constructed as a working contact and adapted to preparatorily close the local circuit of the printing magnet.

12. A telegraph system, comprising two telegraph stations and a line between the two stations including two current paths, each of said stations being provided with two current sources of different dimensions connected in series, a sending contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the paths of the line, a polarized receiving relay interposed in one of the current paths of the line and connected with the sending contact, an auxiliary switch constructed as an alternating contact and suitable to connect the other current path of the line in a nonactuated position with the receiving relay and in the actuated position with the connecting point of the two current sources, and each of said stations also comprising a selector magnet controlled from the receiver relay, mechanical means for selecting a type under the influence of the selector magnet, keys, mechanical means influenced by said keys for controlling the sending contact according to the succession of impulses coordinating with the transmitted signals, an electromagnet for actuating the auxiliary switch, and a connecting key having a contact for closing a circuit for the electromagnet; said connecting key acting on the respective mechanical means for controlling the sending contact and the circuit of the electromagnet for actuating the auxiliary switch being likewise controlled by a contact of the receiver relay.

13. A telegraph system according to claim 12, wherein the mechanical means for controlling the sending contact initiate the emission of a starting impulse, a series of code impulses and a stop impulse, the sending contact in its inoperative position connecting the free pole of the smaller current source with the polarized receiver relay and being suitable, for emitting starting impulses, to connect the free pole of the larger current source with the receiver relay, and said receiver relay being suitable, on closure of a circuit over the larger current source of one of the telegraph stations, to close the circuit for the electromagnet of the auxiliary switch.

14. A telegraph system, comprising two telegraph stations and a line between the two stations including two current paths, each of said stations being provided with two current sources of diiferent dimensions connected in series, a sending contact constructed as an alternating contact and suitable for connecting the free pole of each of the two current sources connected in series with one of the paths of the line, keys, mechanical means controlled by said keys and controlling the sending contact for emitting a starting impulse, a succession of code impulses and a stop impulse; the sending contact connecting the free pole of the larger current source with the one current path of the line; and each of said two stations being further provided with a polarized receiver relay interposed in the one current path of the line and connected with the sending contact, an auxiliary switch constructed as an alternating contact and suitable for connecting the other current path of the line in the non-actuated position with the receiver relay and in the actuated position with the connecting point of both current sources, a selector magnet controlled by the receiving relay, mechanical means for selecting and printing a type under the influence of said selector magnet, an electromagnet for actuating the auxiliary switch, a connecting key having a contact for closing a circuit for the electromagnet, the connecting keys acting on said mechanical means for controlling the sending contact and initiating the emission of a starting impulse, a succession of code impulses similar to the starting impulse and a stop impulse, the circuit of the electromagnet for actuating the auxiliary switch being likewise controlled from the contact of the receiver relay, and the mechanical means for selecting a type being adapted, on actuation of the selector magnet by a succession of code impulses similar to the starting impulse, to prevent the printing of a type. V

15. A telegraph system, comprising two telegraph stations and a line with two current paths between the two stations, each of said stations being provided with a current source, a sending contact, keys, means controlled by the keys and controlling the sending contact for emitting a succession of code impulses, a receiver relay connected with one current path, means controlled from the receiver relay for selecting and printing a type, switch means interrupting in the inoperative state the connection of the current source with at least one current path of the line, and a connecting key, the switch means being controlled by the connecting key as well as by the receiver relay, and said connecting key actuating the means controlling the sending contact for emitting a predetermined succession of code impulses; the receiver relay influencing on the receipt of the predetermined succession of code impulses the switch means for connecting the current source with the line and influencing the means for selecting and for printing a type so as to prevent the printing of a type.

MAX AMANN. 

